I am currently working on a 2D platformer game. For animations I have attached a sprite sheet as a texture to a plane and I cycle through each sprite for animations like a walk cycle. The problem I am facing is how to run 2 animations at a time? For example, what if the player clicks attack and is holding the walk button at the same time. Since the walk has its own sprite sheet and the attack has its own do I need to make another sprite sheet in PS and in that sprite sheet both actions are being performed or is there a way to do this in unity itself?

I would prefer not to use any external plugins for unity, mostly because of the cost but if there is a free one I would love to check it out so please recommend a good one you know.